Vibrator



Sept. 23, 1947. F. A. BURROWS VIBRATOR Filed Nov. 19, 1945 fiwe/z forfiea erz'zielfiarmva fly RM R NA Jig Patented Sept. 23, 1947 VIBBATOBFrederick Arthur Burrows, Wilmette, 111., assignor to Oak Mfg. 00.,Chicago, Ill., a corporation of Illinois Application November 19, 1945,Serial No. 629,556

2 Claim.

This invention relates to a vibrator and particularly .to a highfrequency vibrator for use in interrupting currents. As is well known,automobile and farm radios relying upon batteries as a primary source ofpower utilize vibrators for interrupting direct current and stepping upsuch interrupted currents in a transformer. The resuiting stepped-upvoltages are then used in a conventional manner for supplying the platecircuits of vacuum tubes.

While conventional vibrators operated at around 100 to 110 cycles arehighly satisfactory, there has long existed a demand for vibratorscapable of operating at substantially higher frequencies. As is wellknown, the higher the frequency of interruption, the smaller becomes thephysical size of transformer and filter components. While attempts havebeen made to provide vibrators operating at high frequencies, suchattempts have generally been unsuccessful. In the main, such attemptshave consisted in utilizing conventional vibrating structures and merelyincreasing the stiffness to thereby increase the resonant frequency ofthe vibrating system. The resulting high frequency vibrator hasinvariably had contact trouble and spring breakage.

In accordance with the invention, there is pro- .vided a structure whichis mechanically different than a conventional vibrator and providessatisfactory operation at frequencies between 200 and 300 cycles persecond. In general, a structure embodying the invention utilizes asolenoid instead of an electromagnet for generating the magnetic forcenecessary to attract an armature. An armature cooperates with thesolenoid, and the relationship between the two is such that the solenoidgoes through the position at which it normally would rest upon solenoidenergization. In distinction to present vibrators where the armaturesweeps past a pole face, the driving circuit may be maintained energizedup to the dead center position of the armature. In the conventional typeof vibrator, the driving circuit energization period is more criticalwith respect to the armature rest position. In general, it is preferredto mount the armature at opposite ends thereof on springs and utilizethe armature movement for driving contacts. As will be apparent later,various modifications of the invention are possible, some of thesemodifications being shown in the drawing.

Thus, referring to the drawings, Figure 1 shows a structure embodyingone form of the invention, the structure being shown in elevation withthe solenoid and stack being shown in section. Fig- 56 ly in section, ofa push-pull form of vibrator. Referring now to Figures 1 and 2, thestructure comprises frame members It and ll of steel, brass or any othermetal or material. Members l0 and i I have one end Joined by cylinder i2over which coil i3 is wound. Cylinder l2 preferably is of magneticmaterial and has smooth bore it within the same in which armature i5 isadapted to operate. Armature l5 may consist simply of a ferromagneticmachined cylinder so proportioned as to be freely movable within borei4. Armature I5 is substantially shorter than the length of 0011 IS, theproportion as shown being somewhat greater than one-half. However, theproportion of cylinder length to coil length may vary within wide limitsand will depend upon various factors such as armature travel, frequencyof operation, ratio of coil diameter to coil length, flux density withinarmature i5 and the like.

Armature i5 is supported eccentrically of coil I2 by means of shaft IT.This may be of aluminum or brass and may pass through the center ofarmature l5 or may be secured thereto in any desired fashion. Whileshaft i1 is preferably non-magnetic, its small diameter makes itunimportant whether it is magnetic or non-magnetic. Shaft I! hasthreaded ends l8 and i9.

Frame members l0 and II at the other ends carry outwardly extendingstacks2ll and 2|. Between the ends of members Ill and II is block 22 ofmetal or insulation. The stacks are bolted as shown to provide a rigidstructure. Stack 20 carries a pair of fixed contact supporting members23 and 24 of suitable spring material such as spring steel or berylliumcopper. Contact carrying members 23 and 24 are bent outwardly away fromeach other and carry fixed contacts 21 and '28. These contacts may be ofany suitable material such as silver, tungsten, Or the like.

Cooperating with fixed contacts 21 and 28 are movable contacts 30 and 3|carried on spring arms 32 and 33 diverging from central springsupporting member 34. These arms may be riveted or otherwise fastened tomember: 34. In the normal rest position of the vibrator, movablecontacts 30 and 3| are separated from the cooperating fixed contacts.

Center arm I4 extends upwardly from the stack and its free end 35, issuitably apertured and locked between nuts 36 on threaded end I8 ofshaft l1.

Stack 2| carries fixed driving contact 31 mounted on spring arm 38 ofthe same general shape as arms 24 and 25. Cooperating with fixed contactI1 is movable contact 39 carried on arm 40 branching from sprin llsupported in stack 2i. Spring arm ll has its free end 42 suitablyapertured and locked between nuts 43 at threaded end IQ of shaft l1.

As is well known, vibrators may either have the driving contacts inseries With the driving coil or in shunt thereto. If the drivingcontacts are in series, the normal rest position of the vibrator is suchas to have the contacts closed. On the other hand, if the drivingcontacts are in shunt to the driving coil, then the normal rest positionof the contacts is open. In such a case, it is customary to dispose thedriving coil in series with a primary winding of a transformer, all wellknown in the art. In this particular instance, the driving contacts arein series with driving coil I3, and these contacts are thereforenormally closed.

The spring arms carrying the various contacts are adjusted so that, inthe normal rest position, the driving contacts are closed as shown, andthe power contacts are open. It is evident that the armature should beon the same side of the center of the coil as the driving contacts. Whenenergized, driving coil I3 will generate a magnetic field tending tomove armature l5 toward the left. This will tend to close power contacts30 and 21 and open drivin contacts 3'! and 39. As armature 15 moves intobore-l4, it reaches a dead center position where the effect of themagnetic field on the armature is a maximum, The driving contacts shouldbe so adjusted as to open at or just prior to dead center.

By adjustment of the contact spacing, mass of the armature and vibratingsystem, spring tension, it is possible to provide for such an amplitudeof movement of armature l5 as to effect a desired and satisfactoryclosure of power contacts l and 21 without undue hammerin of thesecontacts. When driving contacts 3'! and 39 are opened, coil I3 becomesdeenergized. Thus, the energy stored in the springs of the vibratortends to return armature l toward a normal rest position. In this returnmovement,

armature l5 will overshoot the position indicated in Figure 1, thusclosing power contacts 34 and 28. At the same time, driving contacts 39and 31 will be closed. By proper design of the inductance of the coiland adjustment of driving contacts, it is possible to provide for aclosure of the driving contacts so that a retarding force or movementofthe armature toward the right of the position shown in Figure 1 willbe generated.

It is, thus, clear that the power contacts may be closed without unduehammering. By virute of the arrangement of the contact supporting arms,a wiping action of the contacts will also result, thus tending to keepthem clean. In general, the driving contacts may engage with more forcethan the power contacts. The driving contacts as a rule do not carryvery heavy currents so that but little contact trouble is experienced.

It is evident that driving contacts 31 and 39 may be entirelyeliminated, and coil l3 may be 4 connected across one of the powercontacts, contacts 21 and II in this particular case.

The amplitude of vibration of armature II is preferably small enough forsatisfactory vibrator operation. The clearance between the armature andbore of cylinder I! should be great enough so that no physical contactor sticking can occur.

Referring now to Figures 3 to 5 inclusive, a modified structure is shownwherein the spring mounting for the contacts and armature has beenchanged. In this particular construction, stacks 50 and Si carry fixedcontacts I! to 54 inclusive. These contacts may be mounted on straightspring arms with contacts 52 and 53 being power contacts and I4 being adriving contact. Frame members I II and II' extend below coil l3 andcarry stacks 50 and I1. Stack 58 carries spring 68 at the free end ofwhich are mounted movable powercontacts OI cooperating with fixedcontacts 52 and II respectively. Spring 58 has portion 5| cut out andsmall spring 82 left therein. Small spring 62 is fastened to shaft ll'in any suitable fashion.

Stack 51 carries spring arm 04 at the free end of which movable drivingcontacts 85 is secured. Spring arm 84 is rigidly fastened to shaft H asshown, and may have the same cut-out con struction as spring arm 50. Bycontrolling the spacers in the various stacks, as well as by bending thevarious spring arms, adjustment of contact spacing may be made.

Referring now toFigure 6, a push-pull type 'of construction is 'shownwherein driving coils Ma and 13b are provided. Shaft Ha carriesarmatures l5a and 15b spaced as shown. These armatures are disposedaxially away from the centers of the corresponding actuating coil. Powercontacts 21", 2|, 30 and II are mounted as shown on spring arms carriedby stack 20. Spring arm 34' carries driving contact 10 c0- operatingwith fixed driving contact ll carried by spring arm 12 supported instack 13.

Stack 2| carries spring arm 15 riveted to shaft l1. Spring arm 15carries driving contact 16 at the free end thereof, this cooperatingwith contact H carried by stack". Inthe normal position of the device,one of the pairs of driving contacts, here shown as 16 and I1, isnormally closed. Upon the energization of the circuit with theconnections as shown, coil lib will be initially energized. Thus,armaturecisb. will be pulled inwardly to the left. After drivingcontacts 16 and 11 open, driving contacts I0 and 1! will close. It isunderstood that both sets of driving contacts will have no over-lappingclosure time. When driving contacts H and 10 are closed, armature I in.will be pulled back into coil I341 tending to reverse the movement ofthe vibratory structure.

, It is clear, therefore, that a push-pull action will result.

It is understood that one movable driving contact may cooperate with afixed driving contact on each side to alternately engage. Also, onearmature, here l5a, may be disposed in a dead center position as thenormal rest position. Thus, on closure of contacts .10 and II, armaturel5a would be left of dead center.

The spring structure of the fixed and movable contact arms may be asshown in Patent 2,140,792. In addition, it is possible to utilize thebifilar construction disclosed in Patent 2,012,123 for reducing arcingat the contacts. The vibrator will have the connections shown and, inaddition, will be connected to suitable batteries and transformers, allwell known in the art.

What is claimed is:

1. In a vibrator, a solenoid including a magnetizing coil, supportingmembers extending to a supporting structure from said solenoid sidestransversely of the solenoid axis, a rod and armature assembly disposedwithin said solenoid, leaf springs carried by said structure, said leafsprings being normally parallel to each other and normal to the solenoidaxis and having cut-outs leaving small spring portions fastened to saidrod ends, said leaf springs normally providing an eccentric restposition for said armature and permitting armature movement along saidsolenoid axis, contacts carried by at least one of said leaf springs, atleast one stack carried by said structure, flxed contacts carried bysaid stack for cooperation with sald movable contact and conmotion;between said magnetizing coil and contacts for maintaining continuousvibration upon energization.

2. In a vibrator. a solenoid including a pair of magnetizing coilsaligned in side-by-side relation and having acontinuous bore, supportingmembers extending from said solenoid sides transversely of the solenoidaxis, a rod and two armatures disposed 'within said solenoids, leafsprings carried by said supports and being normally parallel to eachother and normal to the solenoid axis and supporting said rod at theends thereof to per- 6 mit said armatures to move axially within saidbore, a driving contact secured to each spring,

fixed contacts carried by said supports cooperating with said drivingcontacts, said armatures being so disposed relative to said solenoids sothat only one armature is in a dead center position at one time, one ofsaid pairs of driving contacts being normally closed and connectionsbetween said solenoids and driving contacts whereby pushpull vibratoraction occurs.

FREDERICK ARTHUR. BURROWS.

REFERENCES CITED The following references are of record in the file ofthis patent:

. UNITED STATES PATENTS Number Name Date 1,745,878 Trumpler Feb. 4, 19301,877,480 Osborne Sept. 13, 1932 2,284,891 Hartig June 2, 1942 2,140,792Dressel et al Dec. 20, 1938 I 2,213,854 Wood Sept. 3, 1940 431,493 VanDepoele .July 1, 1890 545,149 Carpenter Aug. 27, .1895 1,124,470 LeBlankJan. 12, 1915 1,855,859 Lesh Apr. 26, 1932 1,954,575 Pearson Apr. 10,1934 2,253,267 Dietrich Aug. 19, 1941

